Civilization 2. I was watching my brother-in-law playing it, thinking this must be some sort of simulation that was part of his college homework. After all, I had played F16 Fighting Falcon in my middle school science class as part of an assignment.
But, no, it was a game for fun. I became enamored with it and it began my love for 4X games that continues to this day.
It's an iterative process, going from messengers, to telegraph, to phones, etc. All in the pursuit of interconnectedness and information exchange. It's kind of hit it's peak with information exchange, being near instant. I can see virtual worlds being the next step (definitely why there's a push towards things like the Metaverse) to achieve even more interconnectedness. An environment where you can be whoever you want and look however you want has appeal. It's still too early for it to catch on with the masses, and also to know what the ramifications will be from people who will look to always be in that world.
Joke answer: Third Impact/Human Instrumentality Project
Sid Meier's Civilization: Beyond Earth. There are other less then stellar games in the Civ franchise that I haven't played like Starships. Beyond Earth, though, was a day 1 purchase for me, and it wasn't -terrible-, but it left a lot to be desired.